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Gstir T, Sundelin D, Michaelsen T, Ayasli A, Swaraj D, Judy J, Zappa F, Geppert W, Wester R. Reaction dynamics of the methoxy anion CH 3O - with methyl iodide CH 3I. Faraday Discuss 2024; 251:573-586. [PMID: 38770842 PMCID: PMC11349062 DOI: 10.1039/d3fd00164d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2023] [Accepted: 02/07/2024] [Indexed: 05/22/2024]
Abstract
Studying larger nucleophiles in bimolecular nucleophilic substitution (SN2) reactions bridges the gap from simple model systems to those relevant to organic chemistry. Therefore, we investigated the reaction dynamics between the methoxy anion (CH3O-) and iodomethane (CH3I) in our crossed-beam setup combined with velocity map imaging at the four collision energies 0.4, 0.7, 1.2, and 1.6 eV. We find the two ionic products I- and CH2I-, which can be attributed to the SN2 and proton transfer channels, respectively. The proton transfer channel progresses in a previously observed fashion from indirect to direct scattering with increasing collision energy. Interestingly, the SN2 channel exhibits direct dynamics already at low collision energies. Both the direct stripping, leading to forward scattering, and the direct rebound mechanism, leading to backward scattering into high angles, are observed.
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Affiliation(s)
- Thomas Gstir
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, 6020 Innsbruck, Austria.
| | - David Sundelin
- Department of Physics, Stockholm University, 106 91 Stockholm, Sweden
| | - Tim Michaelsen
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, 6020 Innsbruck, Austria.
| | - Atilay Ayasli
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, 6020 Innsbruck, Austria.
| | - Dasarath Swaraj
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, 6020 Innsbruck, Austria.
| | - Jerin Judy
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, 6020 Innsbruck, Austria.
| | - Fabio Zappa
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, 6020 Innsbruck, Austria.
| | - Wolf Geppert
- Department of Physics, Stockholm University, 106 91 Stockholm, Sweden
| | - Roland Wester
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, 6020 Innsbruck, Austria.
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2
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Tasi DA, Czakó G. Benchmark ab initio characterization of the complex potential energy surfaces of the HOO - + CH 3Y [Y = F, Cl, Br, I] reactions. Phys Chem Chem Phys 2024; 26:16048-16059. [PMID: 38779842 DOI: 10.1039/d4cp01071j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2024]
Abstract
The α-effect is a well-known phenomenon in organic chemistry, and is related to the enhanced reactivity of nucleophiles involving one or more lone-pair electrons adjacent to the nucleophilic center. The gas-phase bimolecular nucleophilic substitution (SN2) reactions of α-nucleophile HOO- with methyl halides have been thoroughly investigated experimentally and theoretically; however, these investigations have mainly focused on identifying and characterizing the α-effect of HOO-. Here, we perform the first comprehensive high-level ab initio mapping for the HOO- + CH3Y [Y = F, Cl, Br and I] reactions utilizing the modern explicitly-correlated CCSD(T)-F12b method with the aug-cc-pVnZ [n = 2-4] basis sets. The present ab initio characterization considers five distinct product channels of SN2: (CH3OOH + Y-), proton abstraction (CH2Y- + H2O2), peroxide ion substitution (CH3OO- + HY), SN2-induced elimination (CH2O + HY + HO-) and SN2-induced rearrangement (CH2(OH)O- + HY). Moreover, besides the traditional back-side attack Walden inversion, the pathways of front-side attack, double inversion and halogen-bond complex formation have also been explored for SN2. With regard to the Walden inversion of HOO- + CH3Cl, the previously unaddressed discrepancies concerning the geometry of the corresponding transition state are clarified. For the HOO- + CH3F reaction, the recently identified SN2-induced elimination is found to be more exothermic than the SN2 channel, submerged by ∼36 kcal mol-1. The accuracy of our high-level ab initio calculations performed in the present study is validated by the fact that our new benchmark 0 K reaction enthalpies show excellent agreement with the experimental data in nearly all cases.
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Affiliation(s)
- Domonkos A Tasi
- MTA-SZTE Lendület Computational Reaction Dynamics Research Group, Interdisciplinary Excellence Centre and Department of Physical Chemistry and Materials Science, Institute of Chemistry, University of Szeged, Rerrich Béla tér 1, Szeged H-6720, Hungary.
| | - Gábor Czakó
- MTA-SZTE Lendület Computational Reaction Dynamics Research Group, Interdisciplinary Excellence Centre and Department of Physical Chemistry and Materials Science, Institute of Chemistry, University of Szeged, Rerrich Béla tér 1, Szeged H-6720, Hungary.
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3
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Tsutsumi T, Ono Y, Taketsugu T. Reaction Space Projector (ReSPer) for Visualizing Dynamic Reaction Routes Based on Reduced-Dimension Space. Top Curr Chem (Cham) 2022; 380:19. [PMID: 35266073 DOI: 10.1007/s41061-022-00377-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Accepted: 02/21/2022] [Indexed: 11/26/2022]
Abstract
To analyze chemical reaction dynamics based on a reaction path network, we have developed the "Reaction Space Projector" (ReSPer) method with the aid of the dimensionality reduction method. This program has two functions: the construction of a reduced-dimensionality reaction space from a molecular structure dataset, and the projection of dynamic trajectories into the low-dimensional reaction space. In this paper, we apply ReSPer to isomerization and bifurcation reactions of the Au5 cluster and succeed in analyzing dynamic reaction routes involved in multiple elementary reaction processes, constructing complicated networks (called "closed islands") of nuclear permutation-inversion (NPI) isomerization reactions, and elucidating dynamic behaviors in bifurcation reactions with reference to bundles of trajectories. Interestingly, in the second application, we find a correspondence between the contribution ratios in the ability to visualize and the symmetry of the morphology of closed islands. In addition, the third application suggests the existence of boundaries that determine the selectivity in bifurcation reactions, which was discussed in the phase space. The ReSPer program is a versatile and robust tool to clarify dynamic reaction mechanisms based on the reduced-dimensionality reaction space without prior knowledge of target reactions.
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Affiliation(s)
- Takuro Tsutsumi
- Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo, 060-0810, Japan
| | - Yuriko Ono
- Institute for Chemical Reaction Design and Discovery (WPI-ICReDD), Hokkaido University, Sapporo, 001-0021, Japan
| | - Tetsuya Taketsugu
- Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo, 060-0810, Japan.
- Institute for Chemical Reaction Design and Discovery (WPI-ICReDD), Hokkaido University, Sapporo, 001-0021, Japan.
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4
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Meng F, Li Y, Wang D. Predicting atomic-level reaction mechanisms for S N2 reactions via machine learning. J Chem Phys 2021; 155:224111. [PMID: 34911303 DOI: 10.1063/5.0074422] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Identifying atomic-level reaction mechanisms is an essential step in chemistry. In this study, we develop a joint-voting model based on three parallel machine-learning algorithms to predict atomic-level and dynamical mechanisms trained with 1700 trajectories. Three predictive experiments are carried out with the training trajectories divided into ten, seven, and five classes. The results indicate that, as the number of trajectories in each class increases from the ten- to five-class model, the five-class model converges the fastest and the prediction success rate increases. The number of trajectories in each experiment to get the predictive models converged is 100, 100, and 70, respectively. The prediction accuracy increases from 88.3% for the ten-class experiment, to 91.0% for the seven-class, and to 92.0% for the five-class. Our study demonstrates that machine learning can also be used to predict elementary dynamical processes of structural evolution along time, that is, atomic-level reaction mechanisms.
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Affiliation(s)
- Fanbin Meng
- School of Medical Information Engineering, Jining Medical University, Jining 272067, Shandong, China
| | - Yan Li
- College of Physics and Electronics, Shandong Normal University, Jinan 250014, Shandong, China
| | - Dunyou Wang
- College of Physics and Electronics, Shandong Normal University, Jinan 250014, Shandong, China
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5
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Tsutsumi T, Ono Y, Taketsugu T. Visualization of reaction route map and dynamical trajectory in reduced dimension. Chem Commun (Camb) 2021; 57:11734-11750. [PMID: 34642706 DOI: 10.1039/d1cc04667e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In the quantum chemical approach, chemical reaction mechanisms are investigated based on a potential energy surface (PES). Automated reaction path search methods enable us to construct a global reaction route map containing multiple reaction paths corresponding to a series of elementary reaction processes. The on-the-fly molecular dynamics (MD) method provides a classical trajectory exploring the full-dimensional PES based on electronic structure calculations. We have developed two reaction analysis methods, the on-the-fly trajectory mapping method and the reaction space projector (ReSPer) method, by introducing a structural similarity to a pair of geometric structures and revealed dynamic aspects affecting chemical reaction mechanisms. In this review, we will present the details of these analysis methods and discuss the dynamics effects of reaction path curvature and reaction path bifurcation with applications to the CH3OH + OH- collision reaction and the Au5 cluster branching and isomerization reactions.
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Affiliation(s)
- Takuro Tsutsumi
- Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan.
| | - Yuriko Ono
- Institute for Chemical Reaction Design and Discovery (WPI-ICReDD), Hokkaido University, Sapporo 001-0021, Japan
| | - Tetsuya Taketsugu
- Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan. .,Institute for Chemical Reaction Design and Discovery (WPI-ICReDD), Hokkaido University, Sapporo 001-0021, Japan
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6
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Papp P, Czakó G. Rotational Mode Specificity in the F - + CH 3I( v = 0, JK) S N2 and Proton-Transfer Reactions. J Phys Chem A 2020; 124:8943-8948. [PMID: 33054214 PMCID: PMC7604870 DOI: 10.1021/acs.jpca.0c08043] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
![]()
Quasiclassical
trajectory computations are performed for the F– + CH3I(v = 0, JK) →
I– + CH3F (SN2) and HF + CH2I– (proton-transfer)
reactions considering initial rotational states characterized by J = {0, 2, 4, 6, 8, 12, and 16} and K =
{0 and J} in the 1–30 kcal/mol collision energy
(Ecoll) range. Tumbling rotation (K = 0) counteracts orientation effects, thereby hindering
the SN2 reactivity by about 15% for J =
16 in the 1–15 kcal/mol Ecoll range
and has a negligible effect on proton transfer. Spinning about the
C–I bond (K = J), which is
21 times faster than tumbling, makes the reactions more direct, inhibiting
the SN2 reactivity by 25% in some cases, whereas significantly
enhancing the proton-transfer channel by a factor of 2 at Ecoll = 15 kcal/mol due to the fact that the
spinning-induced centrifugal force hinders complex formation by breaking
H-bonds and activates C–H bond cleavage, thereby promoting
proton abstraction on the expense of substitution. At higher Ecoll, as the reactions become more direct, the
rotational effects are diminishing.
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Affiliation(s)
- Paszkál Papp
- MTA-SZTE Lendület Computational Reaction Dynamics Research Group, Interdisciplinary Excellence Centre and Department of Physical Chemistry and Materials Science, Institute of Chemistry, University of Szeged, Rerrich Béla tér 1, Szeged H-6720, Hungary
| | - Gábor Czakó
- MTA-SZTE Lendület Computational Reaction Dynamics Research Group, Interdisciplinary Excellence Centre and Department of Physical Chemistry and Materials Science, Institute of Chemistry, University of Szeged, Rerrich Béla tér 1, Szeged H-6720, Hungary
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7
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Numerical separation of the front-side attack and double-inversion retention pathways of SN2 reactions. Chem Phys Lett 2020. [DOI: 10.1016/j.cplett.2020.137780] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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8
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Li Y, Li Y, Wang D. The importance of the composite mechanisms with two transition states in the F - + NH 2I S N2 reaction. Phys Chem Chem Phys 2020; 22:12929-12938. [PMID: 32453309 DOI: 10.1039/d0cp01942a] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The dynamics of the bimolecular nucleophilic substitution (SN2) reactions at nitrogen are less understood than those of their corresponding reactions at carbon. In this paper, we report an ab initio molecular dynamics approach to investigate the reaction mechanisms of the F- + NH2I SN2 reaction at nitrogen. We found not only the one-transition-state mechanisms, but also the composite mechanisms with two and three transition states. For the two-transition-state mechanisms, the double inversion mechanism and the proton-abstraction roundabout followed by the backside-attack reaction mechanism have been reported before; but we discovered that there is also a new, front-side attack followed by the backside-attack Walden-inversion mechanism. Furthermore, a composite mechanism with three transition states also shows up in the reactive trajectories. Our results show that, as the collision energy increases, the SN2 reactivity decreases, and the proton-abstraction reactivity increases. The two-transition-state mechanisms, especially the double-inversion mechanism, make the largest contribution to the SN2 reactivity, followed then by the one-transition-state mechanisms, with the three-transition-state mechanism contributing the least. The potential energy profiles of the reaction mechanisms are characterized at the CCSD(T)/aug-cc-pVTZ(PP) level of theory. The analysis on stationary points shows that the proton-abstraction inversion transition state is ∼12.4 kcal mol-1 lower than the Walden-inversion transition state in contrast to the corresponding reaction at carbon F- + CH3I, in which the former is ∼26.1 kcal mol-1 higher than the latter. This might explain why the composite mechanism of the double inversion mechanism contributes the most to the SN2 reactivity in the F- + NH2I reaction.
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Affiliation(s)
- Yan Li
- College of Physics and Electronics, Shandong Normal University, Jinan 250014, Shandong, China.
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9
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Tsutsumi T, Ono Y, Arai Z, Taketsugu T. Visualization of the Dynamics Effect: Projection of on-the-Fly Trajectories to the Subspace Spanned by the Static Reaction Path Network. J Chem Theory Comput 2020; 16:4029-4037. [DOI: 10.1021/acs.jctc.0c00018] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Takuro Tsutsumi
- Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo 060-0810, Japan
| | - Yuriko Ono
- Institute for Chemical Reaction Design and Discovery (WPI-ICReDD), Hokkaido University, Sapporo 001-0021, Japan
| | - Zin Arai
- Academy of Emerging Sciences, Chubu University, Kasugai, Aichi 487-8501, Japan
| | - Tetsuya Taketsugu
- Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo 060-0810, Japan
- Institute for Chemical Reaction Design and Discovery (WPI-ICReDD), Hokkaido University, Sapporo 001-0021, Japan
- Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan
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10
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Bastian B, Michaelsen T, Li L, Ončák M, Meyer J, Zhang DH, Wester R. Imaging Reaction Dynamics of F -(H 2O) and Cl -(H 2O) with CH 3I. J Phys Chem A 2020; 124:1929-1939. [PMID: 32050071 PMCID: PMC7197043 DOI: 10.1021/acs.jpca.0c00098] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
![]()
The
dynamics of microhydrated nucleophilic substitution reactions
have been studied using crossed beam velocity map imaging experiments
and quasiclassical trajectory simulations at different collision energies
between 0.3 and 2.6 eV. For F–(H2O) reacting
with CH3I, a small fraction of hydrated product ions I–(H2O) is observed at low collision energies.
This product, as well as the dominant I–, is formed
predominantly through indirect reaction mechanisms. In contrast, a
much smaller indirect fraction is determined for the unsolvated reaction.
At the largest studied collision energies, the solvated reaction is
found to also occur via a direct rebound mechanism. The measured product
angular distributions exhibit an overall good agreement with the simulated
angular distributions. Besides nucleophilic substitution, also ligand
exchange reactions forming F–(CH3I) and,
at high collision energies, proton transfer reactions are detected.
The differential scattering images reveal that the Cl–(H2O) + CH3I reaction also proceeds predominantly
via indirect reaction mechanisms.
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Affiliation(s)
- Björn Bastian
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria
| | - Tim Michaelsen
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria
| | - Lulu Li
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning 116023, China
| | - Milan Ončák
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria
| | - Jennifer Meyer
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria
| | - Dong H Zhang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning 116023, China
| | - Roland Wester
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria
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11
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Tasi DA, Győri T, Czakó G. On the development of a gold-standard potential energy surface for the OH− + CH3I reaction. Phys Chem Chem Phys 2020; 22:3775-3778. [DOI: 10.1039/c9cp07007a] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
We develop the first accurate full-dimensional ab initio PES for the OH− + CH3I SN2 and proton-transfer reactions treating the failure of CCSD(T) at certain geometries.
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Affiliation(s)
- Domonkos A. Tasi
- MTA-SZTE Lendület Computational Reaction Dynamics Research Group
- Interdisciplinary Excellence Centre and Department of Physical Chemistry and Materials Science
- Institute of Chemistry
- University of Szeged
- Szeged H-6720
| | - Tibor Győri
- MTA-SZTE Lendület Computational Reaction Dynamics Research Group
- Interdisciplinary Excellence Centre and Department of Physical Chemistry and Materials Science
- Institute of Chemistry
- University of Szeged
- Szeged H-6720
| | - Gábor Czakó
- MTA-SZTE Lendület Computational Reaction Dynamics Research Group
- Interdisciplinary Excellence Centre and Department of Physical Chemistry and Materials Science
- Institute of Chemistry
- University of Szeged
- Szeged H-6720
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12
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Czakó G, Győri T, Olasz B, Papp D, Szabó I, Tajti V, Tasi DA. Benchmark ab initio and dynamical characterization of the stationary points of reactive atom + alkane and SN2 potential energy surfaces. Phys Chem Chem Phys 2020; 22:4298-4312. [DOI: 10.1039/c9cp04944d] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We review composite ab initio and dynamical methods and their applications to characterize stationary points of atom/ion + molecule reactions.
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Affiliation(s)
- Gábor Czakó
- MTA-SZTE Lendület Computational Reaction Dynamics Research Group
- Interdisciplinary Excellence Centre and Department of Physical Chemistry and Materials Science
- Institute of Chemistry
- University of Szeged
- Szeged H-6720
| | - Tibor Győri
- MTA-SZTE Lendület Computational Reaction Dynamics Research Group
- Interdisciplinary Excellence Centre and Department of Physical Chemistry and Materials Science
- Institute of Chemistry
- University of Szeged
- Szeged H-6720
| | - Balázs Olasz
- MTA-SZTE Lendület Computational Reaction Dynamics Research Group
- Interdisciplinary Excellence Centre and Department of Physical Chemistry and Materials Science
- Institute of Chemistry
- University of Szeged
- Szeged H-6720
| | - Dóra Papp
- MTA-SZTE Lendület Computational Reaction Dynamics Research Group
- Interdisciplinary Excellence Centre and Department of Physical Chemistry and Materials Science
- Institute of Chemistry
- University of Szeged
- Szeged H-6720
| | - István Szabó
- MTA-SZTE Lendület Computational Reaction Dynamics Research Group
- Interdisciplinary Excellence Centre and Department of Physical Chemistry and Materials Science
- Institute of Chemistry
- University of Szeged
- Szeged H-6720
| | - Viktor Tajti
- MTA-SZTE Lendület Computational Reaction Dynamics Research Group
- Interdisciplinary Excellence Centre and Department of Physical Chemistry and Materials Science
- Institute of Chemistry
- University of Szeged
- Szeged H-6720
| | - Domonkos A. Tasi
- MTA-SZTE Lendület Computational Reaction Dynamics Research Group
- Interdisciplinary Excellence Centre and Department of Physical Chemistry and Materials Science
- Institute of Chemistry
- University of Szeged
- Szeged H-6720
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